cutting a mesh object into equal segments for individual export to .dae
Go in edit mode with Tab
Select a loop where you want a cut with Alt+RMB

hit V to cut and RMB to cancel movement

Repeat this all along your mesh on the same axis

Now on the other axis, Alt+RMB the 1st loop and Shift+Alt+RMB to add the cut loops to your selection

hit V to cut and RMB to cancel movement, repeat on the same axis

You can select each separate part with mouse over and L but...

Select all with A and hit P then select by loose part in the separate menu

now every square is a separate object sharing the same material and keeping the UV

Don't forget to change the origins if needed, by default they'll use the base object's origin.